@function remove-unit($number) {
	$unit: unit($number);
	$one: 1;

	@if $unit == "px" { $one: 1px; }
	@if $unit == "em" { $one: 1px; }
	@if $unit == "%"  { $one: 1px; }

	@return $number / $one;
}

@function flex($target, $context, $unit: "em") {
	$size: remove-unit($target) / remove-unit($context);

	@if $unit == "em" 	{ @return #{$size}em; }
	@if $unit == "%" 	{ @return percentage($size); }
}

@function perc($target, $context) { @return flex($target, $context, "%"); }
@function em($target, $context:$fontSizeDefault) { @return flex($target, $context, "em"); }